Nonvolatile flash memory with HfO2 nanocrystal

Abstract

In the present invention, an Hf-silicate film with small nanocrystal of high density is grown through a Rapidly Temperature Annealing (RTA) process, where its manufacturing procedure is simple and can be integrated into modern IC manufacturing procedure to be applied in related industries of memory and semiconductor, such as flash memory, nonvolatile memory, and so on, without extra equipment or process.

1 . A nonvolatile flash memory with HfO 2  nanocrystal, at least comprising: 
 a substrate;    a hafnium-silicate (Hf-silicate) film deposed on said    substrate; and    a control gate layer formed on said Hf-silicate film.    
     
     
         2 . The nonvolatile flash memory according to  claim 1 , wherein said substrate is a p-type silicon wafer.  
     
     
         3 . The nonvolatile flash memory according to  claim 1 , wherein said substrate is put into a vacuum environment.  
     
     
         4 . The nonvolatile flash memory according to  claim 3 , wherein said vacuum environment is filled with argon (Ar) and oxygen (O 2 ).  
     
     
         5 . The nonvolatile flash memory according to  claim 1 , wherein a method for preparing said Hf-silicate film at least comprises steps of: 
 (a) obtaining an Hf and an Si as target materials to be co-sputtered to obtain said Hf-silicate film; and    (b) in an environment of high vacuum with O 2 , passing said Hf-silicate film through a Rapidly Temperature Annealing (RTA) under 900 for 60 seconds to obtain nanocrystal on said Hf-silicate film.    
     
     
         6 . The nonvolatile flash memory according to  claim 5 , wherein the density of said nanocrystal is a value between 0.9×10 12  cm −2  and 1.9×10 12  cm −2 .  
     
     
         7 . The nonvolatile flash memory according to  claim 5 , wherein the size of said nanocrystal is smaller than 10 nm (nanometer).  
     
     
         8 . The nonvolatile flash memory according to  claim 1 , wherein the thickness of said Hf-silicate film is thinner than 30?.  
     
     
         9 . The nonvolatile flash memory according to  claim 1 , wherein said control gate layer is formed on said Hf-silicate film by using a thermal coater.  
     
     
         10 . The nonvolatile flash memory according to  claim 1 , wherein said control gate layer is made of aluminum (Al).  
     
     
         11 . A nonvolatile flash memory with HfO 2  nanocrystal, at least comprising: 
 a substrate;    a tunnel oxide grown at the center on an end surface of said substrate by using a vertical furnace;    an Hf-silicate film formed on said tunnel oxide;    a blocking oxide deposited on said Hf-silicate film by way of Plasma Enhance Chemical Vapor Deposition; and    a control gate layer formed on said blocking oxide.    
     
     
         12 . The nonvolatile flash memory according to  claim 11 , wherein said substrate is a p-type Si wafer.  
     
     
         13 . The nonvolatile flash memory according to  claim 11 , wherein formed at two sides of said substrate is selected from a group consisting of an n +  source and an n +  drain.  
     
     
         14 . The nonvolatile flash memory according to  claim 11 , wherein a method for preparing said Hf-silicate film at least comprises steps of: 
 (a) obtaining an Hf and an Si as target materials to obtain said Hf-silicate film through physical chemical synthesis; and    (b) in an environment of high vacuum with O 2 , passing said Hf-silicate film through an RTA under 900 for 60 seconds to obtain nanocrystal on said Hf-silicate film.    
     
     
         15 . The nonvolatile flash memory according to  claim 14 , wherein said physical chemical synthesis is a method of selected from a group consisting of Atomic Layer Chemical Vapor Deposition, High-Density Plasma Chemical Vapor Deposition, sputtering and Electron-Gun Vacuum-Evaporation.  
     
     
         16 . The nonvolatile flash memory according to  claim 14 , wherein said Hf-silicate film is further selected from a zirconium silicate (Zr-silicate) film and an Hf-aluminate film.  
     
     
         17 . The nonvolatile flash memory according to  claim 14 , wherein the density of said nanocrystal is a value between 0.9×10 12  cm −2  and 1.9×10 12  cm −2 .  
     
     
         18 . The nonvolatile flash memory according to  claim 14 , wherein the size of said nanocrystal is smaller than 10 nm.  
     
     
         19 . The nonvolatile flash memory according to  claim 11 , wherein the thickness of said Hf-silicate film is thinner than 30?.  
     
     
         20 . The nonvolatile flash memory according to  claim 11 , wherein the thickness of said tunnel oxide is 20?.  
     
     
         21 . The nonvolatile flash memory according to  claim 11 , wherein said tunnel oxide is a chemical vapor deposition oxide.  
     
     
         22 . The nonvolatile flash memory according to  claim 11 , wherein said tunnel oxide is a high-k dielectric.  
     
     
         23 . The nonvolatile flash memory according to  claim 11 , wherein the thickness of said blocking oxide is 40?.  
     
     
         24 . The nonvolatile flash memory according to  claim 11 , wherein said blocking oxide is made of a material selected from a group consisting of an oxide, a nitride, HfO 2 , ZrO 2 , Al 2 O 3  and La 2 O 3 .  
     
     
         25 . The nonvolatile flash memory according to  claim 11 , wherein said control gate layer is formed on said Hf-silicate film by using a thermal coater.  
     
     
         26 . The nonvolatile flash memory according to  claim 11 , wherein said control gate layer is made of a material selected from a group consisting of Al, polysilicon, germanium polysilicon and a metal.  
     
     
         27 . The nonvolatile flash memory according to  claim 11 , wherein the structure of said nonvolatile flash memory is a SONOS (Silicon-Oxide-Nitride-Oxide-Silicon) structure.  
     
     
         28 . A nonvolatile flash memory with HfO 2  nanocrystal, at least comprising: 
 a substrate;    a tunnel oxide grown at the center on an end surface of said substrate;    an Hf-silicate film formed on said tunnel oxide;    a blocking oxide formed on said Hf-silicate film;    a polysilicon formed on said blocking oxide; and    an interval layer formed at two sides of said tunnel oxide, said Hf-silicate film, said blocking oxide, and said polysilicon.    
     
     
         29 . The nonvolatile flash memory according to  claim 28 , wherein said nonvolatile flash memory is a single dot memory.  
     
     
         30 . The nonvolatile flash memory according to  claim 28 , wherein the structure of said substrate is a SOI (Silicon-On-Insulator) structure.  
     
     
         31 . The nonvolatile flash memory according to  claim 28 , wherein a method for preparing said Hf-silicate film at least comprises steps of: 
 (a) obtaining an Hf and an Si as target materials to be co-sputtered to obtain said Hf-silicate film; and    (b) in an environment of high vacuum with O 2  passing said Hf-silicate film through an RTA under 900 for 60 seconds to obtain nanocrystal on said Hf-silicate film.    
     
     
         32 . The nonvolatile flash memory according to  claim 31 , wherein the density of said nanocrystal is a value between 0.9×10 12  cm −2  and 1.9×10 12  cm −2 .  
     
     
         33 . The nonvolatile flash memory according to  claim 31 , wherein the size of said nanocrystal is smaller than 10 nm.  
     
     
         34 . The nonvolatile flash memory according to  claim 28 , wherein the thickness of said Hf-silicate film is thinner than 30?.  
     
     
         35 . A nonvolatile flash memory with HfO 2  nanocrystal, at least comprising: 
 a substrate including a first Si layer on a SiO 2  layer and a second Si layer grown at the center on an end surface of said SiO 2  layer;    a tunnel oxide formed at two sides on an end surface of said SiO 2  layer and upon said second Si layer;    an Hf-silicate film formed on said tunnel oxide;    a hard mask formed on an end surface between said tunnel oxide and said Hf-silicate film;    a blocking oxide formed on said Hf-silicate film; and    a control gate layer formed on said blocking oxide,    wherein a plurality of control gates is formed in a way of chemical mechanical polishing (CMP) on said control gate layer by removing the part of said control gate layer which is right upon an end surface of said blocking oxide.    
     
     
         36 . The nonvolatile flash memory according to  claim 35 , wherein said nonvolatile flash memory is a multi-bits single-dot memory.  
     
     
         37 . The nonvolatile flash memory according to  claim 35 , wherein the structure of said substrate is a SOI structure.  
     
     
         38 . The nonvolatile flash memory according to  claim 35 , wherein a method for preparing said Hf-silicate film at least comprises steps of: 
 (a) obtaining an Hf and an Si as target materials to be co-sputtered to obtain said Hf-silicate film; and    (b) in an environment of high vacuum with  02 , passing said Hf-silicate film through an RTA under 900 for 60 seconds to obtain nanocrystal on said Hf-silicate film.    
     
     
         39 . The nonvolatile flash memory according to  claim 38 , wherein the density of said nanocrystal is a value between 0.9×10 12  cm −2  and 1.9×10 12  cm 2 .  
     
     
         40 . The nonvolatile flash memory according to  claim 38 , wherein the size of said nanocrystal is smaller than 10 nm.  
     
     
         41 . The nonvolatile flash memory according to  claim 35 , wherein the thickness of said Hf-silicate film is thinner than 30?.  
     
     
         42 . The nonvolatile flash memory according to  claim 35 , wherein said hard mask is made of Si 3 N 4 .